JPH0344695A - Data storing method for character generator - Google Patents

Abstract

PURPOSE:To reduce the storage capacity of the character generator by providing header data which represents necessary characteristics of image data at the head of hexadecimal data showing each lateral array of an image pattern and omitting the storage of necessary data. CONSTITUTION:A character generator ROM 3 is stored with the hexadecimal data showing each lateral array of the image pattern. A header indicating how many there are the same data following the header continuously is provided at the head part of this data and the storage of the same data in the ROM 3 is omitted. Consequently, the storage capacity of the dot image pattern of the character generator is reducible and the constitution of the character generator is reduced in size.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data storage method for a character generator.

[Prior Art] For example, when storing a dot image pattern represented by 30 vertical dots x 32 horizontal dots as shown in FIG. 4(a) in a character generator, the dot image pattern shown in FIG. 4(b) is 1 unit is 8 dots, and each unit is 16 4 dots.
It is expressed as 1-byte data in a hexadecimal code, and one horizontal column is represented by 4-byte image data. Then, one dot image pattern is stored as image data by converting this into a decimal number in the vertical direction.

A character generator is constructed by storing such data for a large number of characters, numbers, etc.

[Problems to be Solved by the Invention] However, in this method of storing one dot image pattern by converting 4-byte image data into 30-digit numbers in the vertical direction, Even when the same image data is repeatedly arranged in the vertical direction as shown in , it is necessary to store each image data.
If such data storage is performed for a large number of characters, numbers, etc., there is a problem in that the data storage capacity required for the character generator becomes enormous.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a data storage method for a character generator that can save data storage capacity and thus be downsized.

[Means and effects for solving the problem] The present invention converts a dot image pattern of letters, numbers, symbols, etc. into hexadecimal code image data for each horizontal row of the dot image pattern, and stores the converted image data in a character generator. In this case, header data is provided at the beginning of the image data, and the header data is used as data indicating how many consecutive identical image data items are present after the image data to which the header data is attached. The reason is that the storage of image data is omitted.

That is, although header data indicating the number of images is added, it is possible to eliminate repeated storage of the same image data.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. Note that the present invention will be described as applied to a character generator for a laser printer.

Figure 1 is a block diagram showing the configuration of a laser printer.
is a CPU (central processing unit) that constitutes the main body of the control unit, 2
3 is a program ROM (read only memory) that stores program data for controlling each part of this CPU 1, and 3 is an image data for converting print data into a dot image pattern, which corresponds to a large number of characters, numbers, etc. A character generator ROM provided as
4 is a raster RAM (random access memory) for developing print data converted into a dot image pattern, and 5 is an external interface for receiving print data from an externally connected host computer.

The CPUI and each ROM 2.3, RAM 4, and interface 5 are connected via a path line 6.

The dot image pattern developed in the raster RAM 4 is sent to the print control unit 8 via the video interface 7.
is being supplied to.

The printing control unit 8 controls a laser scanner, a photosensitive drum, a charging unit,
A printing mechanism section 9 consisting of a transfer section, a fixing section, etc. is driven and controlled to perform a printing operation.

The character generator ROM 3 stores, for example, characters in a dot image pattern as shown in FIG. 2(a) as image data as shown in FIG. 2(b). In other words, for a dot image pattern of 30 dots vertically x 32 dots horizontally, 8 dots are placed at 111th position, and it is
Each dot is expressed as 1-byte data in hexadecimal code, and one horizontal column is expressed as 4-byte image data as shown by ■ in FIG. 2(b). At the beginning of the image data, header data as shown in (b) of FIG. 2 is added.

The header data is composed of one byte and indicates the number of repetitions of the same image data after the image data to which the header data is added. In other words, in the part marked ■ in (b) of Figure 2, the same image data is repeated 8 times after the first image data, so the header data added to the first image data is "8".
” is specified. Also, ■ in (b) of Figure 2
Since the same image data is repeated twice after the first image data, "2" is specified in the header data added to the first image data. Further, in the part (■) in FIG. 2(b), since the same image data is repeated 10 times after the first image data, rAJ is specified by the header data added to the first image data. The same image data that is repeated is omitted.

When the CPUI reads data from the character generator ROM 3 and performs printing control, it performs the processing shown in FIG. 3. That is, first, the first image data of the image data corresponding to the print data is read out, and the added header data is read out. Then, the same image data is repeatedly arranged the number of times specified in the header data. When this is completed, the next image data is read and the added header data is also read. Then, the same image data is repeatedly arranged the number of times specified in the header data.

The above process is repeated until the character structure is completed, and when the reading for one character is completed, the dot pattern data based on the read image data is stored in the raster RAM.
Expand to 4. The dot pattern data is then read from the raster RAM 4 and supplied to the print control section 8 for printing.

In this embodiment with such a configuration, header data specifying the number of repetitions of the image data is added to the beginning of the image data, and instead, the repeated image data is omitted and stored in the character generator ROM 3. Therefore, for example, considering a portion where the same image data is repeated once, it increases by 1 byte but decreases by 4 bytes, resulting in a reduction in memory capacity of 3 bytes. Considering the character rHJ in Figure 2, 1-byte header data is added in 10 places, so it increases by 10 bytes, but there are 20 places where 4-byte image data is repeated, so it decreases by 80 bytes. In total, 70 bytes of memory capacity can be saved.

Therefore, it is possible to save a considerable amount of memory capacity for characters and numbers that appear repeatedly in the same image data. A considerable amount of memory capacity can be saved and the device can be made smaller.

When reading image data from the character generator ROM 3, the ladder data is read and the image data for a specified number of times are repeatedly arranged to form a character, and a dot image pattern is developed in the raster RAM 4 based on the formed characters. Therefore, the original dot image pattern can be reliably reproduced.

In the above embodiments, the present invention is applied to a character generator for a laser printer, but the present invention is not necessarily limited to this, and can be applied to character generators used for other printers and display devices. It is.

[Effects of the Invention] As detailed above, according to the present invention, header data is provided to specify the number of repetitions of the same image data,
Instead, since the same image data that is repeated is omitted, it is possible to save data storage capacity and thus provide a data storage method for a character generator that can be made smaller.

[Brief explanation of drawings]

1 to 3 show embodiments of the present invention.
2 is a schematic diagram showing the relationship between the dot image pattern and the content of image data stored in the character generator. FIG. 3 is a flowchart showing the image data reading process by the CPU. FIG. 4 is a schematic diagram showing the relationship between a dot image pattern and the contents of image data stored in a conventional character generator. 1...CPU (central processing unit),

Claims (1)

[Claims] When converting each horizontal row of dot image patterns such as letters, numbers, symbols, etc. into hexadecimal code image data and storing it in a character generator, header data is provided at the beginning of the image data, and the A character generator characterized in that the header data is data indicating the number of consecutive identical image data items after the image data to which the header data is attached, and storage of consecutive identical image data is omitted. Data storage method.